Not getting the other brush to function , my question is that can you have two brushes in dynamicpainting painting the same canvas. ?
Yes, you can.
... "any" number of mesh objects (set as Brush) should work for the same Canvas object.
Blender Manual for more info check Dynamic Paint
When you have any issue, it is always good way to open a new file and test it with maximum of default setups, if still issue "Load factory settings" and test again.
BTW answering given Q didn't move you forward and didn't solve your issue ... try to edit your Q with something more specific that we can solve for you :)